In constructing a fluid flow transfer device using a pleated membrane such as a hemodialyzer, it is desirable to anchor the membrane tips on the blood (or other fluid to be dialyzed) side to the apparatus housing interior to direct the blood flow into the spaces between the membrane folds and prevent shunting of blood from inlet to outlet without being dialyzed between the folds. One problem has been development of a simple but effective method of anchoring the tips. One proposed method of anchoring the membrane tips is that invented by Thomas E. Goyne and involves injecting liquid adhesive potting material into a housing that is positioned horizontally, as are the membrane tips, to produce uniformity of potting.
Even with uniform potting, however, the problem of achieving a bond that will not fail has persisted, including in the situation in which the pleated membrane is treated with a plasticizer such as glycerin. One basis for the problem is that in normal operation a dialyzer will have a higher pressure on the blood side of the membrane, a pressure that will tend to force the membrane away from the potting. One way of strengthening the bond is by increasing the membrane tip surface area embedded in the potting. However, if one simply allows the potting to flow freely to cover more of the tip surface area, the potting may flow too far into the spaces between the membrane folds and block the fluid flow passages therein, thus impairing the efficiency of the device.